Toothpaste hurts your guy's nuts?

So I just recently found out you can really hurt a guys nuts just by having them come into contact with toothpaste. I really don't know why the method isn't very popular it's such and easy form of humiliation, I could put a guy through a world of hurt just buy rubbing a little toothpaste across the back of his nuts while he's sleeping🤣
Balls really must be alot more sensitive than I thought, it'd have to be pretty embarrassing to be in that much pain from such little effort.